browser-testing-with-devtools

# Browser Testing with DevTools ## Overview Use Chrome DevTools MCP to give your agent eyes into the browser. This bridges the gap between static code analysis and live browser execution — the agent can see what the user sees, inspect the DOM, read console logs, analyze network requests, and capture performance data. Instead of guessing what's happening at runtime, verify it. ## When to Use - Building or modifying anything that renders in a browser - Debugging UI issues (layout, styling, interaction) - Diagnosing console errors or warnings - Analyzing network requests and API responses - Profiling performance (Core Web Vitals, paint timing, layout shifts) - Verifying that a fix actually works in the browser - Automated UI testing through the agent **When NOT to use:** Backend-only changes, CLI tools, or code that doesn't run in a browser. ## Setting Up Chrome DevTools MCP ### Installation Add the following to your project's `.mcp.json` or Claude Code settings: ```json { "mcpServers": { "chrome-devtools": { "command": "npx", "args": ["-y", "chrome-devtools-mcp@latest", "--isolated"] } } } ``` `-y` skips the npx install confirmation. By default the server launches Chrome with its own dedicated profile (under `~/.cache/chrome-devtools-mcp/`), separate from your personal browser; `--isolated` goes one step further and uses a temporary profile that is wiped when the browser closes. This is the right setup for most testing. There is also `--autoCo...